scholarly journals Parametrized black hole quasinormal ringdown. II. Coupled equations and quadratic corrections for nonrotating black holes

2019 ◽  
Vol 100 (4) ◽  
Author(s):  
Ryan McManus ◽  
Emanuele Berti ◽  
Caio F. B. Macedo ◽  
Masashi Kimura ◽  
Andrea Maselli ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Coupled Equations

scholarly journals REGULAR BLACK HOLES IN AN ASYMPTOTICALLY DE SITTER UNIVERSE

2008 ◽  
Vol 23 (40) ◽  
pp. 3377-3392 ◽  
Author(s):  
JERZY MATYJASEK ◽  
DARIUSZ TRYNIECKI ◽  
MARIUSZ KLIMEK
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Nonlinear Electrodynamics ◽  
Spherically Symmetric ◽  
De Sitter ◽  
Coupled Equations ◽  
Sitter Universe ◽  
De Sitter Universe ◽  
Horizon Geometry ◽  
Interesting Solution

A regular solution of the system of coupled equations of the nonlinear electrodynamics and gravity describing static and spherically-symmetric black holes in an asymptotically de Sitter universe is constructed and analyzed. Special emphasis is put on the degenerate configurations (when at least two horizons coincide) and their near horizon geometry. It is explicitly demonstrated that approximating the metric potentials in the region between the horizons by simple functions and making use of a limiting procedure one obtains the solutions constructed from maximally symmetric subspaces with different absolute values of radii. Topologically they are AdS2×S2 for the cold black hole, dS2×S2 when the event and cosmological horizon coincide, and the Plebański–Hacyan solution for the ultraextremal black hole. A physically interesting solution describing the lukewarm black holes is briefly analyzed.

Thermodynamics of new black hole solutions in the Einstein–Maxwell-dilaton gravity

2018 ◽  
Vol 27 (07) ◽  
pp. 1850073 ◽  
Author(s):  
M. Dehghani
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Fields ◽  
Dilaton Gravity ◽  
Field Equations ◽  
Two Phase ◽  
Transition Analysis ◽  
Coupled Equations ◽  
Scalar Field Equations ◽  
Black Hole Solutions

In the present work, thermodynamics of the new black hole solutions to the four-dimensional Einstein–Maxwell-dilaton gravity theory have been studied. The dilaton potential, as the solution to the scalar field equations, has been constructed out by a linear combination of three Liouville-type potentials. Three new classes of charged dilatonic black hole solutions, as the exact solutions to the coupled equations of gravitational, electromagnetic and scalar fields, have been introduced. The conserved charge and mass of the new black holes have been calculated by utilizing Gauss's electric law and Abbott–Deser mass proposal, respectively. Also, the temperature, entropy and the electric potential of these new classes of charged dilatonic black holes have been calculated, making use of the geometrical approaches. Through a Smarr-type mass formula, the intensive parameters of the black holes have been calculated and validity of the first law of black hole thermodynamics has been confirmed. A thermal stability or phase transition analysis has been performed, making use of the canonical ensemble method. The heat capacity of the new black holes has been calculated and the points of type one- and type two-phase transitions as well as the ranges at which the new charged dilatonic black holes are locally stable have been determined, precisely.

scholarly journals Black holes in Gauss–Bonnet and Chern–Simons-scalar theory

2019 ◽  
Vol 28 (09) ◽  
pp. 1950114 ◽  
Author(s):  
Yun Soo Myung ◽  
De-Cheng Zou
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Perturbation Equation ◽  
Schwarzschild Black Hole ◽  
Scalar Theory ◽  
Coupled Equations ◽  
Klein Gordon ◽  
The Stability ◽  
Chern Simons ◽  
Metric Perturbation

We carry out the stability analysis of the Schwarzschild black hole in Gauss–Bonnet and Chern–Simons-scalar theory. Here, we introduce two quadratic scalar couplings ([Formula: see text]) to Gauss–Bonnet and Chern–Simons terms, where the former term is parity-even, while the latter one is parity-odd. The perturbation equation for the scalar [Formula: see text] is the Klein–Gordon equation with an effective mass, while the perturbation equation for [Formula: see text] is coupled to the parity-odd metric perturbation, providing a system of two coupled equations. It turns out that the Schwarzschild black hole is unstable against [Formula: see text] perturbation, leading to scalarized black holes, while the black hole is stable against [Formula: see text] and metric perturbations, implying no scalarized black holes.

scholarly journals Morphological evolution of supermassive black hole merger hosts and multimessenger signatures

2021 ◽  
Vol 503 (3) ◽  
pp. 3629-3642
Author(s):  
Colin DeGraf ◽  
Debora Sijacki ◽  
Tiziana Di Matteo ◽  
Kelly Holley-Bockelmann ◽  
Greg Snyder ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Star Formation ◽  
Morphological Evolution ◽  
Full Range ◽  
High Mass ◽  
Morphological Evidence ◽  
Galaxy Mergers ◽  
Host Galaxies ◽  
Supermassive Black Hole

ABSTRACT With projects such as Laser Interferometer Space Antenna (LISA) and Pulsar Timing Arrays (PTAs) expected to detect gravitational waves from supermassive black hole mergers in the near future, it is key that we understand what we expect those detections to be, and maximize what we can learn from them. To address this, we study the mergers of supermassive black holes in the Illustris simulation, the overall rate of mergers, and the correlation between merging black holes and their host galaxies. We find these mergers occur in typical galaxies along the MBH−M* relation, and that between LISA and PTAs we expect to probe the full range of galaxy masses. As galaxy mergers can trigger star formation, we find that galaxies hosting low-mass black hole mergers tend to show a slight increase in star formation rates compared to a mass-matched sample. However, high-mass merger hosts have typical star formation rates, due to a combination of low gas fractions and powerful active galactic nucleus feedback. Although minor black hole mergers do not correlate with disturbed morphologies, major mergers (especially at high-masses) tend to show morphological evidence of recent galaxy mergers which survive for ∼500 Myr. This is on the same scale as the infall/hardening time of merging black holes, suggesting that electromagnetic follow-ups to gravitational wave signals may not be able to observe this correlation. We further find that incorporating a realistic time-scale delay for the black hole mergers could shift the merger distribution towards higher masses, decreasing the rate of LISA detections while increasing the rate of PTA detections.

scholarly journals Islands and stretched horizon

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Yoshinori Matsuo
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Entanglement Entropy ◽  
Total System ◽  
Island Rule ◽  
Asymptotically Flat ◽  
Flat Spacetime ◽  
Ads Spacetime ◽  
Hole Geometry

Abstract Recently it was proposed that the entanglement entropy of the Hawking radiation contains the information of a region including the interior of the event horizon, which is called “island.” In studies of the entanglement entropy of the Hawking radiation, the total system in the black hole geometry is separated into the Hawking radiation and black hole. In this paper, we study the entanglement entropy of the black hole in the asymptotically flat Schwarzschild spacetime. Consistency with the island rule for the Hawking radiation implies that the information of the black hole is located in a different region than the island. We found an instability of the island in the calculation of the entanglement entropy of the region outside a surface near the horizon. This implies that the region contains all the information of the total system and the information of the black hole is localized on the surface. Thus the surface would be interpreted as the stretched horizon. This structure also resembles black holes in the AdS spacetime with an auxiliary flat spacetime, where the information of the black hole is localized at the interface between the AdS spacetime and the flat spacetime.

scholarly journals Epicyclic Oscillations around Simpson–Visser Regular Black Holes and Wormholes

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 279
Author(s):  
Zdeněk Stuchlík ◽  
Jaroslav Vrba
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Observational Data ◽  
High Frequency ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Periodic Oscillations ◽  
High Length ◽  
Circular Geodesic

We study epicyclic oscillatory motion along circular geodesics of the Simpson–Visser meta-geometry describing in a unique way regular black-bounce black holes and reflection-symmetric wormholes by using a length parameter l. We give the frequencies of the orbital and epicyclic motion in a Keplerian disc with inner edge at the innermost circular geodesic located above the black hole outer horizon or on the our side of the wormhole. We use these frequencies in the epicyclic resonance version of the so-called geodesic models of high-frequency quasi-periodic oscillations (HF QPOs) observed in microquasars and around supermassive black holes in active galactic nuclei to test the ability of this meta-geometry to improve the fitting of HF QPOs observational data from the surrounding of supermassive black holes. We demonstrate that this is really possible for wormholes with sufficiently high length parameter l.

scholarly journals Gravitational and Electromagnetic Perturbations of a Charged Black Hole in a General Gauge Condition

Particles ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 106-128
Author(s):  
Claudia Moreno ◽  
Juan Carlos Degollado ◽  
Darío Núñez ◽  
Carlos Rodríguez-Leal
Keyword(s):  
Black Hole ◽  
Scalar Function ◽  
Gauge Condition ◽  
Fluid Distribution ◽  
Electromagnetic Signal ◽  
Charged Fluid ◽  
Coupled Equations ◽  
Electromagnetic Signals ◽  
Limiting Case ◽  
Weyl Scalar

We derive a set of coupled equations for the gravitational and electromagnetic perturbation in the Reissner–Nordström geometry using the Newman–Penrose formalism. We show that the information of the physical gravitational signal is contained in the Weyl scalar function Ψ4, as is well known, but for the electromagnetic signal, the information is encoded in the function χ, which relates the perturbations of the radiative Maxwell scalars φ2 and the Weyl scalar Ψ3. In deriving the perturbation equations, we do not impose any gauge condition and as a limiting case, our analysis contains previously obtained results, for instance, those from Chandrashekhar’s book. In our analysis, we also include the sources for the perturbations and focus on a dust-like charged fluid distribution falling radially into the black hole. Finally, by writing the functions on the basis of spin-weighted spherical harmonics and the Reissner–Nordström spacetime in Kerr–Schild type coordinates, a hyperbolic system of coupled partial differential equations is presented and numerically solved. In this way, we completely solve a system that generates a gravitational signal as well as an electromagnetic/gravitational one, which sets the basis to find correlations between them and thus facilitates gravitational wave detection via electromagnetic signals.

scholarly journals New non-extremal and BPS hairy black holes in gauged $$ \mathcal{N} $$ = 2 and $$ \mathcal{N} $$ = 8 supergravity

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Andres Anabalon ◽  
Dumitru Astefanesei ◽  
Antonio Gallerati ◽  
Mario Trigiante
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Boundary Conditions ◽  
Charged Black Hole ◽  
Dual Theory ◽  
Real Numbers ◽  
Hairy Black Holes ◽  
Interpolation Parameter ◽  
Black Hole Solutions ◽  
Extremal Black Holes

Abstract In this article we study a family of four-dimensional, $$ \mathcal{N} $$ N = 2 supergravity theories that interpolates between all the single dilaton truncations of the SO(8) gauged $$ \mathcal{N} $$ N = 8 supergravity. In this infinitely many theories characterized by two real numbers — the interpolation parameter and the dyonic “angle” of the gauging — we construct non-extremal electrically or magnetically charged black hole solutions and their supersymmetric limits. All the supersymmetric black holes have non-singular horizons with spherical, hyperbolic or planar topology. Some of these supersymmetric and non-extremal black holes are new examples in the $$ \mathcal{N} $$ N = 8 theory that do not belong to the STU model. We compute the asymptotic charges, thermodynamics and boundary conditions of these black holes and show that all of them, except one, introduce a triple trace deformation in the dual theory.

scholarly journals Driven black holes: from Kolmogorov scaling to turbulent wakes

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Tomas Andrade ◽  
Christiana Pantelidou ◽  
Julian Sonner ◽  
Benjamin Withers
Keyword(s):  
Nonlinear Dynamics ◽  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Strong Field ◽  
De Sitter ◽  
Event Horizons ◽  
Binary Mergers ◽  
Tidal Deformations ◽  
Proof Of Principle

Abstract General relativity governs the nonlinear dynamics of spacetime, including black holes and their event horizons. We demonstrate that forced black hole horizons exhibit statistically steady turbulent spacetime dynamics consistent with Kolmogorov’s theory of 1941. As a proof of principle we focus on black holes in asymptotically anti-de Sitter spacetimes in a large number of dimensions, where greater analytic control is gained. We focus on cases where the effective horizon dynamics is restricted to 2+1 dimensions. We also demonstrate that tidal deformations of the horizon induce turbulent dynamics. When set in motion relative to the horizon a deformation develops a turbulent spacetime wake, indicating that turbulent spacetime dynamics may play a role in binary mergers and other strong-field phenomena.

scholarly journals Uptunneling to de Sitter

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Mehrdad Mirbabayi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
False Vacuum ◽  
De Sitter ◽  
Dimensional Theory ◽  
Hole Geometry ◽  
Horizon Geometry ◽  
Two Sides ◽  
Extremal Black Holes

Abstract We propose a Euclidean preparation of an asymptotically AdS2 spacetime that contains an inflating dS2 bubble. The setup can be embedded in a four dimensional theory with a Minkowski vacuum and a false vacuum. AdS2 approximates the near horizon geometry of a two-sided near-extremal Reissner-Nordström black hole, and the two sides can connect to the same Minkowski asymptotics to form a topologically nontrivial worm- hole geometry. Likewise, in the false vacuum the near-horizon geometry of near-extremal black holes is approximately dS2 times 2-sphere. We interpret the Euclidean solution as describing the decay of an excitation inside the wormhole to a false vacuum bubble. The result is an inflating region inside a non-traversable asymptotically Minkowski wormhole.

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